Connector device for electrically and hydraulically connecting a water-cooled conductor

ABSTRACT

A method of electrically and hydraulically connecting a conductor bar having a plurality of hollow water-cooled conductors involves compressing the conductor bar and shims of brazing material in a connector clip formed of a pair of mating clip members. Brazing shims (strips and bands) are placed in desired positions, and then the components are heated and hydraulically compressed. The conductor bar and brazing material assembly is sized for a tight fit in one dimension, but oversized in another dimension so that compression results in a desired distribution of the molten brazing material. During compression, the clip members are secured from relative motion, other than displacement toward one another, and air is passed through the hollow conductors to prevent the accumulation of brazing material in the open ends thereof. In addition to the clip members, the connector device includes a water inlet member with a stem that is inserted between and brazed to the clip members after the compression step.

This is a division of application Ser. No. 761,446 filed Jan. 21, 1977,now U.S. Pat. No. 4,066,203.

BACKGROUND OF THE INVENTION

Field of the Invention

The present invention relates generally to a method and connector deviceto provide a good electrical and hydraulic connection for a water-cooledconductor, and more specifically, the present invention relates to amethod and connector device for providing a good electrical andhydraulic connection for turbogenerator stator bars formed from aplurality of hollow water-cooled conductors.

Description of the Prior Art

In large turbogenerators, excessive heating can occur due to the verylarge currents that are involved. Accordingly, hollow conductors areutilized so that water may be passed therethrough to remove theundesired heat. Although different shapes may be employed, the mostcommon assembly of water-cooled conductors involves a pair of rows ofgenerally rectangular conductors formed into a generally rectangularconductor bar. These conductor bars are then employed as the windingsfor the extremely large turbogenerators.

Cooling water for the hollow conductors is normally introduced at theend turn area of the turbogenerator windings. A conventional practice isto utilize a connector to which the end of a conductor bar is brazed,with provision for inserting water into the open end of the hollowconductors. The end turns are completed by electrically connectingappropriate connectors.

One type of connector is essentially in the form of a hollow box. Theconductor bar is inserted partially into the connector box and brazed tothe box. Water is then inserted into the other end of the box to bepassed through the open end of the hollow conductors. In order to makesuch an arrangement work, the brazing of the conductor bar to the boxshould be such as to provide a strong mechanical joint, a continuouselectrically conductive path, and a water-tight seal. While prior artapproaches have frequently been able to provide the strong mechanicaljoint, the electrical, and especially the hydraulic, aspects of thesebrazed joints have frequently been deficient.

Prior art brazed joints have conventionally been achieved by feeding thebrazing material along the conductors toward the open ends of the hollowconductors. Such an approach relies upon the capillary action of thebrazing material. Dependence upon the capillary action results in anumber of problems. First of all, in order to keep the brazing materialmoving along the conductors, it is necessary to utilize relatively hightemperatures to achieve brazing material flow along even the relativelylimited length which may be achieved. In addition, the brazing materialtends to flow to the smaller gaps or spaces, and hence it is difficultto get enough brazing material in the relatively larger spaces, such asat the rounded corners of the conductors. Still further, in order toachieve the desired electrical and hydraulic characteristics, both thebox and the conductor bar must be constructed to fairly tight tolerances(a total tolerance in the order of .001 or .002 inch is required), whichis extremely difficult to achieve with a conductor bar. Therefore, manyprior art braze joints exhibit poor electrical characteristics and atendency toward porosity with respect to the cooling water. Inasmuch asthe failure of a large turbogenerator can result in the loss of manytens of thousands of dollars worth of electrical power each day that theturbogenerator is not operating, the failure of a brazed joint is veryserious.

SUMMARY OF THE INVENTION

The method and connector device of the present invention alleviate manyof the problems of prior art devices and permit the establishment of abrazed joint that is not only strong mechanically, but which alsoobviates many of the electrical and hydraulic deficiences of prior artconductor bar connections. Not only is a better braze joint achieved,but the manufacturing process is also simplified with the resultantlower costs.

To achieve these results, applicant employs a pair of mating clipmembers, each of which has a conductor bar receiving chamber portionformed at one end and a larger water cavity portion formed at the otherend. Shims or strips of brazing material are placed between adjacenthollow conductors, which are positioned in two parallel rows about acentral web of conducting material. In addition, bands of the brazingmaterial are located in the conductor bar receiving chamber portions ofthe clip members, as well as on either side of the central web ofconductive material. The bands of brazing material have a thickness suchthat when they are added to the cross-sectional width of the conductorbar the total width is greater than the width of the conductor barreceiving chamber formed by joining the clip members. By some suitableapproach, such as the use of a packing shim of conducting materialhaving an appropriate thickness, the cross-sectional length of the rowsof hollow conductors in the conductor bar is established to provide asnug fit of the conductor bar in the conductor bar receiving chamber.Accordingly, it may be seen that the tolerances of the conductor bar andthe clip members are considerably less demanding than with prior artdevices, as compensations may be easily provided for any discrepancies.

A water inlet member has a stem that is partially inserted into thewater cavity portion of one of the clip members. The conductor bar alsoextends slightly beyond the conductor bar receiving chamber into thewater cavity, but is spaced from the opposing end of the stem of thewater inlet member to permit water to accumulate in this portion of thewater cavity. The water inlet member also has a flange that isapproximately the shape and size of the clip members when joined, aswell as a neck with a central passage which extends on through theflange and the stem to pass water into the water cavity.

With the conductor bar and the associated shims of brazing materialpositioned as indicated, the other clip member is brought adjacent thefirst clip member and the clip members and conductor bar are heated tothe melting temperature of the brazing material. Dowels formed ofconducting material are placed in appropriate openings formed in legsextending from the clip members. These dowels prevent relative motionbetween the clip members, except for displacement of the clip memberstoward one another, during the time that the brazing material is in amolten state. After the brazing material is heated to its meltingtemperature, the clip members are hydraulically compressed so that theyare forced toward one another until they are joined. This action causesthe brazing material to be distributed throughout the assembly,including the formation of reservoirs or pools at relatively largespaces, such as the rounded corners of the conductors, to form thedesired braze joint.

During the time that the clip members are being hydraulicallycompressed, air may be passed through the hollow conductors to blow awayany brazing material that tends to flow into the open ends of theconductors. In this fashion, the build up or accumulation of brazingmaterials in the hollow conductors is prevented.

By this approach, a very desirable braze joint is formed by thecompression of the conductor bar and brazing material between the clipmembers to provide a uniform distribution of brazing material throughoutthe braze joint. After the joining of the clip members, the stem of thewater inlet member is inserted into the water cavity and brazed in placeto provide for the introduction of water into the water cavity.

Since variations and tolerances are easily compensated, themanufacturing process is made much simpler and less costly. In addition,the process may be achieved at lower temperatures than with prior artdevices. These advantages are all supplementary to the production of abraze joint that is a considerable improvement electrically andhydraulically over the braze joints of the prior art.

These and other objects, advantages and features of this invention willhereinafter appear, and for purposes of illustration, but not oflimitation, an exemplary embodiment of the subject invention is shown inthe appended drawing.

BRIEF DESCRIPTION OF THE DRAWING

FIG. 1 is a perspective view of a connection made pursuant to thepresent invention.

FIG. 2 is a side elevational view of the connection of FIG. 1.

FIG. 3 is an enlarged cross-sectional view taken along line 3--3 of FIG.2.

FIG. 4 is a cross-sectional view taken along line 4--4 of FIG. 3.

FIG. 5 is an exploded enlarged view of the connection of FIG. 1 prior tofinal assembly.

FIG. 6 is a perspective view showing the electrical interconnection oftwo connections of the type illustrated in FIG. 1 to complete the endturn of a turbogenerator.

FIG. 7 is a cross-sectional view taken along line 7--7 of FIG. 6.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

With reference to FIG. 1 an electrical and hydraulic connection 11constructed in accordance with the present invention is illustrated. Aconnector device 13 has a pair of mating clip members 15 and 17, each ofwhich has an extending leg section 19 or 21, respectively. A water inletmember 23 has a stem 25 (FIG. 4), a flange 27 and a neck 29. A conductorbar 31 is formed from a plurality of hollow water-cooled conductors 33.Any appropriate number, odd or even, of hollow conductors may beemployed, this preferred embodiment illustrating the use of twenty-onehollow conductors.

In the cross-sectional view of FIG. 4, it may be seen that the clipmember 17 has a conductor bar receiving chamber portion 35. When clipmember 15, and its corresponding conductor bar receiving chamberportion, is joined with clip member 17, the conductor bar receivingchamber 37 (FIG. 3) is established. Similarly, it may be seen that clipmember 17 has a water cavity portion 39 which, when joined with thecorresponding water cavity portion of clip member 15, forms the watercavity 41. The water cavity portion 39 is formed slightly deeper thanthe conductor bar receiving portion 36, so that the water cavity islarger than the conductor bar receiving chamber 37.

By utilization of FIGS. 3, 4 and 5, the method of forming the connectionfor the conductor bar may now be followed. As seen in FIG. 5 shims orstrips of brazing material 43 are positioned between the hollowconductors 33. This brazing material may be any suitable composition,such as a standard alloy of silver, phosphorus and copper sold by Handyand Harman under the trademark "SILFOS". The shims or strips 43 may beof any desired thickness, the preferred embodiment disclosed hereinemploying strips of .005 inch thickness.

A pad of conductive material 45 is located at one end of the conductorbar 31. This conductive pad 45 may be formed of any suitable conductivematerial, such as an oxygen-free high conductivity copper. Pad 45 has ashim 47 of spacing material on either side thereof. These shims 47 mayalso have a thickness of 0.005 inch. Additional shims 49 are locatedabove pad 45 to form a brazed connection beween top edges 51 and 53 ofclip members 15 and 17, respectively.

The two rows of hollow conductors 33 are separated by a conductive web55. Web 55 may be any suitable electrically conductive material, such ascopper. On either side of the web 55 there is positioned a shim or bandof conductive material 57. These bands would normally be thicker thanthe strips of brazing material separating the hollow conductors, forexample on the order of 0.020 inch. Other bands or shims of brazingmaterial 59 are located in the conductor bar receiving chamber portionsof the clip members 15 and 17. Bands 59 would normally be thicker thanthe bands 57, in this preferred embodiment being approximately 0.040inch. The thickness of the bands 57 and 59 added to the cross-sectionalwidth of the conductor bar 31 should be greater than the width of theconductor bar receiving chamber 37, so that upon compression of the clipmembers 15 and 17 the molten brazing material will be forced throughoutthe chamber 37 to provide a uniform brazed joint.

The cross-sectional length of a conductor bar 31 should be adjusted tosnuggly fit within the conductor bar receiving chamber 37. Anyappropriate type of adjustment will suffice, such as varying thethickness of the strips or shims 43 or the thickness of the conductivepad 45. However, it has been found preferable to make this adjustment bythe utilization of a packing shim 61. Packing shim 61 is formed ofconductive material and has a thickness such as to provide the desiredsnug fit of conductor bar 31 in conductive bar receiving chamber 37.

Additional shims of brazing material 63 are positioned between the legs19 and 21 of clip members 15 and 17 in order to provide a good brazejoint between these sections of the clip members. It should be notedthat these shims 63 are provided with openings 65 and 67 to align withopenings 69 and 71 in legs 19 and 21. The purpose of these openings 65,67, 69 and 71 is to receive the dowels 73 and 75. Dowels 73 and 75 serveto prevent relative motion between clip members 15 and 17 during thetime that these members are being forced toward one another underhydraulic pressure. Of course, the one motion that the dowels 73 and 75do not interfere with is the displacement of the clip members 15 and 17toward one another.

After the shims have been positioned, the conductor bar 31 is placed inthe conductor bar receiving chamber portion of one of the clip members15 or 17, as may be seen in FIG. 4. An end 77 of conductor bar 31 isextended slightly into the water cavity 41, in order to minimize theamount of brazing material that will tend to flow into the open end ofthe hollow conductors 33. At the other end, the water inlet member 23will have its stem 25 inserted into the water cavity 41, where it shouldfit snuggly. Flange 27 abuts the clip members 15 and 17, while neck 29is adapted to be connected to receive water in a passage 79. Passage 79also extends through flange 27 and stem 25 to convey water to watercavity 41. It should be noted that end 81 is spaced from ends 77 of theconductor bar, so that water fills a portion of the water cavity 41.Further, it should be noted that water inlet member 23 is brazed to clipmembers 15 and 17.

After conductor bar 31, and the appropriate shims of brazing materialhave been positioned in one of the clip members as illustrated in FIG.4, the other clip member is positioned adjacent the first clip memberand heat is applied to raise the temperature of all components to themelting temperature of the brazing material. At this time, clip members15 and 17 are hydraulically forced toward one another to compress thebrazing material and conductor bar 31. As clip member 15 and 17 arehydraulically forced toward one another, the brazing material spreadsuniformly throughout the assembly and collects in little pools orreservoirs at the larger gaps or spaces, such as at the rounded cornersof the conductors 33. Thus, a very strong, uniform and non-porous brazejoint is relatively simply produced.

When the clip members have been joined, the stem 25 of the water inletmember 23 is inserted into the water cavity 41 and the inlet member 23is brazed to clip members 15 and 17.

Turing now to FIG. 6, the completion of an end turn of a turbogeneratoris illustrated. This is achieved by utilizing a connection 11 on the endof each connector bar 31 that is to be connected through the end turn.By having the slightly longer leg 19 of one connection 11 abut theslightly shorter leg 21 of the other, the two connections are properlyaligned and positioned. Series connection pads 85 and 87 may then bebrazed to the outer surface of the legs to form a permanent joint. Thebrazing material utilized for this joint should have a lower meltingtemperature than that employed for the shims, strips and bands in theconductor bar receiving chamber, in order to prevent any interferencewith that brazed joint. An example of such a lower temperature brazingalloy is that sold under the trademark "EASIFLO 45", a compound whichincludes a higher percentage of silver.

It should be understood that various modifications, changes andvariations may be made in the arrangement, operation and details ofconstruction of the elements disclosed herein without departing from thespirit and scope of this invention.

I claim:
 1. A connecting device employed in forming an electrical andhydraulic connection for receiving a conductor bar assembly ofpredetermined size, said device comprising:a pair of clip members havinga generally rectangular body section and mating surfaces; a conductorbar receiving chamber portion extending inwardly from one end of each ofsaid clip members; a larger water cavity portion extending inwardly fromthe other end of each of said clip members; and a water inlet member tointroduce water into said cavity, said water inlet member having a stemto extend partially into said water cavity with a tight fit, a flange ofgenerally the same cross-sectional size and shape as said clip memberswhen said clip members are joined together, and an elongated neck with acentral passage that continues through said flange and said stem toconvey water to said water cavity; whereby, the chamber formed by theconductor bar receiving chamber portion of said pair of joined togetherclip members is slightly smaller than said predetermined size of saidconductor bar assembly.
 2. The connecting device of claim 1 wherein:ashim member of fusible material is located between the mating surfacesof said pair of clip members, said shim member being melted in situ forjoining said pair of clip members together.
 3. The connecting device ofclaim 1 wherein:first shim members of fusible material having apredetermined size are located on the interior surfaces of saidconductor bar receiving chamber portions, said first shim members beingmelted in situ to join said clip members to the conductor bar assembly.4. The connecting device of claim 3 wherein:said conductor bar assemblyincludes individual conductors joined together by second shim members offusible material melted in situ; said mating clip members are joinedtogether by third shim members of fusible material which are melted insitu; said first, second and third shim members are all melted in situat substantially the same time to form an integral connecting device. 5.A connector assembly of a pair of connecting devices employed in formingan electrical and hydraulic connection for receiving a conductor barassembly of predetermined size, each of said connecting devicescomprising:a pair of clip members having a generally rectangular bodysection and mating surfaces, said pair of clip members being joinedtogether; a leg depending from each of said clip members having a freeend, an attached end, and a mating surface, said mating surfaces of eachleg opposing end other when said clip members are joined together, oneof said legs being longer than the other and having an extended matingsurface which extends beyond the free end of said other leg; saidconnecting devices being assembled such that the free ends of saidlonger and shorter legs of one of said pair of clip members is mated tothe free ends of said shorter and longer legs of the other of said pairof clip members respectively; and means for joining the shorter andlonger legs of one of said pair of clip members to the shorter andlonger legs of the other of said pair of clip members.
 6. A connectorassembly as recited in claim 5 wherein:each leg of each connectingdevice has an outer surface; said joining means includes a connectionpad fused to the outer surfaces of said longer and shorter legs whosefree ends are mated together.